Method of and apparatus for receiving radiosignals



July 28,1925] W. L. CARLSON METHOD OF AND APPARATUS FOR RECEIVING RADIOS IGNALS Filed Feb. 14,

Y Ifivenio-F Wendell -L Carlson ttorney WWDELL L. CARLSDN,

M F WAISHINGTON, DISTRIGT 0F (ZGLUMBKA.

METHOD 0]? All?!) MPARALTUS FOR RECEIVING RADIOSIGNMS.

Application filed February I l, 2852. florist Ho. 53$,l96.

To all whom it may concem:

Beit known that I, WENDELL L. (Benson,

a citizen of the United States of America,-

and resident of Washington, District of Columbia, have invented certain new and useful Improvements in Methods of and Apparatus for Receiving Radiosignals, of which the following is a specification.

generally toradio particularly to receivio, signals, and has for a particular object theeflicient reception of signals Without employing the well-known heterodyne method of reception, refer ence being made to U. 8. Patents Nos. 1,050,-

Myinvention relates signaling, and more mg rad 441 and 1,050,728 to Fessenden, granted stance, it willbe readily pedients will hate the desired signal when understood by reference vantage has been dug the beat having heated filament F,

anuary 14, 1913.

One of the .beat method advantages claimed for the of reception is that by adjusting the frequency of the local source of oscillations, the-frequency of the beats may be regulated to give a note best suited tot-he car of the operator. This same adobtained without employmethod, reference being made to U. S. Patent 1,170,552 to Meissner, granted February 8, 1916. By adj usting the local source of low frequency oscillations be made in the of Meissner, a change can to be suitable to note inthe receiver so as (the ear of the operator.

; There are certain disadvantages in the 'methodproposed by eissner and it is the purpose of my invention to render more etective this mode of reception. For inobvious that to rethe local signals must be come weak signals at the ear entirely eliminated ator Wh Wise, it will be difficult to recognize the real signals when they come through. Meissner endeavors to accomplish this by loose coupling and tuning, but it is doubtful if the local signals can be entirely eliminated in this Way, and it is certain that these exgreatly reduce or even elimithe arrangement is actuated by a Weak incoming signal. e manner in which I have improved method of receiving signals will best be to the drawing.

is an ordinary B-electrode vacuum tube plate P and grid he grid-filament circuit of thistube is excited through transformer T by a local source of audible oscillations, which source regulated at the generator amount of coupling in transformer T. The platefilament circuit is excited by the incoming signals received on antenna A, the strength of such excitation being boosted if necessary by a series of 3-electrode vacuum tube amplifiers A A A and A, and their circuits, or other suitable feeble electric current amplifiers. A, is also a 3-electrode vacuum tube amplifier which may be inserted after the tube V to intensify the final signal in telephones P or other suitable responsive L, and L, are lines supplying elec-. trical energy for heating the filaments or" all of the vacuum tubes, the amount of such energy being controlled by ballast lamps B,,'

Lines L, and L supply energy for exciting the plate-filament circuits'of the amplifiers, it being general to control the potential on these circuits at the source. It Will be noted that tube V is not excited from this source. rhcostat it permits of securing an adjustable ative bias on the plate of tube V.

follows: The

rent flow Or should there be a slight flow from whatever cause, this can be eliminated by giving the plate P a. slight negative bias. through cont-act C or by adjusting the temperature of the filament F through contact 6,, or by proper adjustment of both Having no-sounol in the telephones P, nal is received on the antenna A, it excites the plate-filament circuit of the tube V, rendering the plate P alternately positive and negative at a frequency in keeping with that of the incoming signal. plate P is made positive a currentfiows in.

adjusted so that there is when asig Contact 0, on the Every time the the tube, and therefore in the plate-filament circuit. These high frequency uni-directional current pulses are modulated by the local oscillations exciting the grid G at an audible rate with the result that the in coming signal manifests itsel'l in telephones P through a note in accordance with the local oscillations. It is obvious that this note can be regulated by the operator to suit his own peculiarities it he is provided With a local generator variable in frequency.

Having fully described my invention, what I desire to secure by Letters Patent is:

1. The method of receiving and translate mg into a signal radio frequency signalropresenting energy, which comprises receiving the signal-representing energy, and rectifying the current thereof in a circuit Whose impedance is always finite, independently generating an electromotive force varying in amplitude at predetermined frequency, producing variations of impedance of said circuit by said electromotive force only When said signal-representing energy is being received and translating into a signal the rectified current as modified by said impedance variation.

2. In a receiver of high frequency electrical oscillations, a three-electrode vacuum tube, means for exciting the grid-filament circuit of said tube With locally generated oscillations, means for negatively biasing the plate of said tube, means for exciting the plate-filament circuit of said tube With the high frequency oscillations, and means for observing the resultant current flow in said plate-filament circuit, N

In a receiver of high frequency electrical oscillations, a three-electrode vacuum tube, means for exciting the, grid-filament circuit ofsaid tube with locally generated oscillations, means for adjusting the condition of the electrodes of said tube to prevent a current fiow in its plate-filament circuit, due to said local excitationymeans for exciting said plate-filament circuit with the high frequency oscillations so as to disturb said adjusted condition of the electrodes of said tube, and meansifor'observing the resultant current flow in the plate-filament circuit' 4. In a radio receiving system, a plurality of coupled amplifying tubes, one of said tubes having its plate-filament circuit inter posed in its coupling With the preceding tube, a local source of audible oscillations interposed in the grid-filament circuit of he last-named tube, and a negative bias for the plate of said tube.

5. The method of receiving and translating into signals radio frequency signal representing currents, which comprises rectitying the radio signal currents in a circuit in which no current can normally flow, producing variations of impedance in said circuit only when signal-energy is being received, and then translating into'a signal the rectified current as modified by said impedance variations.

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